Asset Management, GIS and LiDAR Projects

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Sign Retroreflectivity

We get a lot of questions about developing the right strategy as it relates to assets that are managed by different agencies. These questions are typically focused on “How” to manage assets, which typically comes after the agency decides “Why” to manage assets.

Here are some typical questions:

When is the best time to manage my asset in its life-cycle?

When do I rehabilitate my asset?

What do I do to the asset?

When do I replace my asset?

Can I just let it runs its course and when it fails, replace it?

Should I invest time and money in an asset early in its life-cycle or wait until it is in poor condition to fix it?

We always recommend starting this process by understanding a few things about the asset.

1. Financial Considerations – How much does an asset cost to install and Maintain? Is it capitalized or not? In most cases, the cost of an asset has a large impact on how it is managed. This is not the only consideration, but we can use it as a starting point.

2. Risk Considerations – What are the consequences to the agency if this asset fails? Will someone get hurt? Will it cause an accident? These are closely tied to other financial considerations such as tort liability.

3. Life-Cycle Considerations – How does the asset typically deteriorate? Is it straight-line deterioration or more of a polynomial-type of a curve? This information helps determine what to do to an asset and when to do it (less cost when starting earlier in the process). Programmatic treatments or inspection-driven treatments are common approaches to managing assets with this approach.

Once an agency has a solid understanding of the Financial, Risk and Life-Cycle considerations related to an asset, they can begin to develop a management strategy specifically for the asset type to be managed. Since every asset can be managed differently, we will focus on a couple of assets and their management strategy.

Pavement

Financial – Capitalized asset – high cost to install and maintain.

Risk – Critical to the movement of people and commerce – high consequence of failure.

Life-Cycle – Long-term asset with long-term life expectancy – Can be managed using a life-cycle or Inspection-based approach.

Pavements have a long history of research and empirical data models that have been developed for Airports, Parking lots and Roads and a variety of software exists to support the maintenance of this asset. Therefore, it is pretty easy to choose an approach to manage pavement based on an agency’s goals and priorities. Typically this program is inspection-driven (every 3-5 years) and focuses on finding the best mix of Preservation and Rehabilitation activities designed to achieve their target Level-of-Service.

Signs

Financial – Capitalized asset – low to high cost to install and maintain.

Risk – Critical to the safety of people and commerce – low to high consequences of failure.

Life-Cycle – Medium to long-term life-expectancy – Can be managed using a life-cycle or Inspection-based approach.

Signs have less empirical data collected for them and can have varied Financial, Risk and Life-cycle information compiled and available throughout the industry. Strategies for management are typically focused on Life-Cycle and Risk and there are many methodologies that are accepted by FHWA. These are outlined in their Manual on Uniform Traffic Control Devices (MUTCD) and are widely utilized throughout the US.

Light Poles

Financial – Capitalized asset – medium cost to install and maintain.

Risk – Semi-Critical to the safety of people and commerce – low to high consequences of failure.

Life-Cycle – Medium to long-term life-expectancy – Can be managed using a life-cycle or Inspection-based approach.

Light poles are typically managed by inspection of their base attachments (every 10 years or so) but many agencies typically run these assets to failure (luminaire failure or pole failure). This is another mixed bag of management because some light poles provide a critical safety function (DOT) and others just light the way for safety (walkways) and are not as critical to the daily operations of an agency.

These are just a few examples of strategy development – we would love to see comments related to the infrastructure that you manage and we will reply with some of the Industry’s Best-Management-Practices (BMPs) that are successfully used throughout the US.

DOTs across the Country are mandated by the Federal Government to keep track of their roadway assets and to report against these assets to receive Federal funding for their maintenance and repair. Many DOTs conduct Roadway Characteristics Inventories (RCI) on an annual basis to update and maintain their data relative to these assets. Traditionally, this has been completed using a boots-on-the-ground approach which has been very effective at building these inventories. Many DOTs are experimenting with other technologies, namely mobile LiDAR, to conduct these inventories and to achieve many other benefits from the 3D data captured in the process.

The next graphic illustrates the typical technology solution utilized for these projects. It is composed of the Riegl VMX-450 LiDAR unit, coupled with High-definition Right-of-Way (ROW) imagery. This system can collect at rates up to 1.1 KHz (1,100,000 pts/sec) at a precision of 5mm. It collects points in a circular (360-degree) pattern along the right-of-way from 2 scanner heads facing forward and to the rear of the vehicle in a crossing pattern. The laser captures 3D points at a density of 0.3 foot at speeds up to 70mph. This scanner can be adjusted to scan at a rate that is applicable for the project specifications to limit the amount of data collected and to ensure that the resulting point cloud data is manageable.

Right-of-Way imagery is also co-collected along with this LiDAR point cloud data. These images are used to identify appropriate attribution for each feature type being extracted from the point cloud. In this example, the DOT has digitized Shoulder, Driveway Culvert Ends, and Drainage Features (Culverts, Ditches and Bottom of Swale). Additional Features such as Signs, Signals, Striping, and Markings will also be extracted and then reported to the Feds on an annual basis. The mobile LiDAR data provides a 3D surface from which to compile the data and then the ROW imagery can be used for contextual purposes to support attribution. This methodology provides an effective process that can be used to create 3D vector layers and accurate attribution used to build a robust Enterprise GIS.

Both the ROW imagery and the mobile LiDAR can be used to collect and extract the RCI data efficiently for the DOTs and provides the DOT with a robust data set that can be leveraged into the future. The ROW imagery is typically used to map features at a mapping-grade level while the LiDAR can vary a bit in accuracy. Since the relative accuracy inherent in the LiDAR is very precise, it is used to conduct dimensional measurements related to clearances, sign panel sizes, lane widths, and other measurements that require a higher precision.

The DOT utilizes the derivative products from this RCI exercise to report to the Feds in a way that is pretty basic, but effective to achieve their level of funding. For example, the data capture is very technical in nature and focuses on high precision and accuracy. Then, the RCI data is extracted from this source data, maintaining a level of precision that is dictated by the source data. Then, the DOT takes this precise data and aggregates it up to a higher level and reports the total number of Signs or the lineal feet of guardrail. Even though the reporting of this data is pretty basic in nature, the origins of the data can still have precision and accuracy and can be used for other purposes related to Engineering Design or Asset Management.

In conclusion, mobile LiDAR and Right-of-Way imagery are a safe and accurate way to collect and report against RCI variables for DOTs. This methodology promotes a safe working environment for both the DOT worker and the traveling public. It is also a cost-effective way to collect large amounts of 3D point cloud data which can be utilized for other purposes within the same Agency.

Over the past few years, there have been many projects designed to determine an agency’s sign retroreflectivity compliance across their road network. Each project has been unique in terms of how the agency collected the data and how they ultimately managed the data into the future. Recent MUTCD regulations require the development of an inventory management program that documents the installation, maintenance and construction characteristics of sign infrastructure. Many agencies are faced with the daunting task of funding a replacement program that will comply with these new regulations into the future. Ultimately, the replacement plan needs to address non-compliance issues that are identified during the inventory/inspection process.

Step 1 – Sign Inventory

The first step in the compliance process begins with an accurate inventory. Signs can be collected utilizing many different techniques and each technique can have its pluses and minuses. Field collection programs can involve inspectors walking the roads, mobile imaging vehicles taking pictures of the roads as well as other collection techniques designed to identify compliance issues along the road. No matter which solution is selected, it needs to satisfy the overall goals and objectives of the project while providing an accurate inventory of the agency’s sign infrastructure.

Next, an agency needs to be able to match their available funding to the technology solution that achieves their project goals and objectives. It also needs to understand the trade-offs that are the necessary evil in projects like this – available funding typically dictates the quality of the solution that can be provided by the service provider. Furthermore, the quality of the data collected and its usefulness can be impacted by the choice of the solution and available funding.

Remember that the ultimate goal of retroreflectivity compliance is centered on the replacement of signs once they fall below the minimum reflectivity standard as defined by FHWA. Many agencies would rather start replacing signs today instead of spending money to create their inventory and a management plan. This makes sense economically in the short-term, but can introduce problems from a long-term management perspective.

Step 2 – Estimating the Replacement Cost of the Sign Network

The next graphic illustrates the total replacement cost as calculated using the FHWA “Sign Retroreflectivity Guidebook” for an agency with a 4,383 centerline mile road network.

The cost to replace all signs for this agency approaches $17.5 million dollars. Please note that this does not include the cost of the labor, equipment and other material costs incurred for the actual installation of these signs. The inventory of signs for this agency cost approximately $800k or roughly 5% of the total replacement cost for these signs. Although significant, this investment is crucial to ensure the longevity of the Sign Management program designed to manage these assets throughout their life-cycle.

Step 3 – Choosing a FHWA-Approved Sign Management Methodology

The chart below illustrates the advantages and disadvantages related to a few of the FHWA-recommended methodologies. Most of these methods have been implemented in one way or another at various agencies across the Country.

The “Measured Retroreflectivity” method is popular at many DOTs and Toll Authorities. I believe this is the case because these agencies typically manage facilities that carry higher volumes of traffic that operate at higher speeds, thus increasing the risk and potential consequences of an accident. Many County and City agencies are utilizing the “Visual Nighttime Inspection, Expected Life, Control Sign, or Blanket Replacement” methods to manage their sign infrastructure. Each mentioned method is used for different reasons (financial vs. headcount) and has a lot to do with legacy management techniques (“We’ve always done it this way”).

There really isn’t a management method that can be considered “The Best” or “The Most Cost-Effective”. It is solely dependent upon an agency’s goals and objectives for the management of their sign infrastructure. I typically recommend conducting an inventory first and then implementing a management plan that uses the concepts of Condition, Risk, and Valuation to help prioritize which signs should be replaced along with the best timing for the replacement. This can prove very valuable since the highest risk signs can be replaced first and the least risky signs can be programmed for replacement as funding becomes available.

Finally, I also recommend that agencies utilize asset management software to manage the work performed on their sign infrastructure so that all replacements can then be managed according to their useful life and actual condition rating. This information can then be used in concert with one another to help develop a capital improvement plan that details the planned fiscal expenditures for the next 10 years, which is the typical life-cycle of a sign.

We’ve built a bunch of new tools centered on pavement crack assessment and we’re excited about how it will increase the transparency related to pavement assessments. In the past, pavement assessments have been more about delivering segments with PCI values attached to them and less about the actual measurements that were used during the creation of this data.

Our clients are always quick to say “We went out and checked a few segments and our assessments were different than what was reported”. This lead to an educational discussion about how the ratings were created and how we applied the ASTM methodology to arrive at these results. Most of the time we all agreed that there was always some subjectivity in the ratings, but that the standard rating methodology had been applied the same way throughout the network.

Our goal has always been to increase the transparency related to pavement inspections and this new approach has helped us to take a step in that direction. The process is GIS-centric, as it is with all of our processes and involved a ton of tool development that will continue to evolve over time. So, here’s what we’re doing…

First, we are collecting crack images using a downward-facing 4k linescan camera system with laser illumination. This ensures that all of the pavement images are uniform and are not subject to low-lighting or shadows from natural and man-made features. These images are 1mm resolution, allowing us to see the detailed cracking – especially at the lowest severity levels.

The following graphic illustrates the output from the crack mapping software we are using. Cracks are identified in the imagery automatically from the software and are exported as geospatial points, lines and polygons.

The software does a great job of identifying longitudinal, transverse, and alligator cracking. Once we have the initial crack map, our team of compilers goes in and edits the crack maps as needed. Typically, we are editing out false-positives and adding in other distresses as dictated by the scope of work. This editing is done within our EarthView software and is completely geospatial in nature. In other words, we can export these cracks, so they can be viewed in a GIS. This is pretty exciting because all of these cracks can be mapped and themed in a GIS based on their severity levels.

This process gives the end user of the data a simple QA/QC process that can be used to understand the specific issues related to each segment. Furthermore, this data is then combined with other GIS data sets (Functional Classification, Traffic Counts, etc.) so that a more holistic approach can be taken towards the determination of which segments need in terms of repair methods. This data can also be exported to Google Earth for easy viewing and display in a non-GIS software.

We hope that this provides the end user with more tools in their GIS arsenal to better plan, bid, and execute their Capital Improvement Planning for the year. In other words, our clients will be able to do more with their limited funding than ever before!

We just completed a sign retroreflectivity shortlist presentation for the a client and discussed the options available for gaining compliance based on FHWA regulations as described in the MUTCD. The client was sold on the “Blanket Replacement” method by a vendor who specializes in sign replacement.

MUTCD Retroreflectivity Guidelines

I was thinking “what a great selling strategy”, but then I thought twice about it. This vendor had the ability to write their own ticket for selling their sign materials! A great strategy for the vendor, but not a good option for the client.

We approached the presentation using a different approach – it combined the concept of risk with the general principles of Asset Management. First, we would inventory their existing sign network to determine what they had and where it was. Then, we would prioritize which areas were the most likely to fail based on the average age of the signs as well as the risk associated with the actual failure (e.g. pedestrian injury or vehicle damage due to an accident).

Risk Assessment for Signs

Sample Replacement Cost Calculation

This approach takes into consideration the entire segment of a road instead of considering an individual asset. The client believes that it is more cost effective to replace the worst signs along a segment using a single mobilization of field crews, rather than jumping around and fixing signs based solely on their condition. Therefore, we are combining the geospatial location, condition, age, value and MUTCD to develop a risk score for each individual sign.

Project Life Cycle

This analysis is used to create the biggest bang for the buck for our client by reducing risk related to accidents caused by failing signs. Since all agencies have to be compliant with Regulatory, Guide and Warning signs by 2015, this approach will support a phased approach while taking care of the highest risk signs and working through the lower risk signs until all non-compliant signs have been replaced or are scheduled for replacement.

Compliance Dates for Sign Retroreflectivity

Valuation of Sign Asset

In conclusion, the use of Risk to support the prioritization of asset maintenance serves an appropriate role in saving clients time and money. By replacing the highest risk assets first, an agency can reduce their exposure to lawsuits related to failing infrastructure.